Normally continuously operating compressor with controls therefor



y 1966 w. w. FULLERTON NORMALLY CONTINUOUSLY OPERATING COMPRESSOR WITH CONTROLS THEREFOR Filed April 24, 1964 KOmWwNEEOU I NVENTOR. WALLACE W. FULLERTON United States Patent Office 'Pafented July 19, 1966 3,261,175 NORMALLY CONTINUOUSLY OPERATING COM- PRESSOR WITH CONTROLS THEREFOR Wallace W. Fullerton, Wayne, Pa., assignor to Vilter Manufacturing Corporation, Milwaukee, Wis, a corporation of Wisconsin Filed Apr. 24, 1964, Ser. No. 362,298 5 Claims. (Cl. 62-197) The present invention relates to improvements in compressor operation, and it relates more particularly to a refrigeration system wherein the compressor is continuously operable regardless of whether it be in loaded or unloaded condition.

A primary object of the invention is to provide improvements in refrigeration systems whereby the refrigerant compressor may be efliciently operated in an unloaded condition as well as in loaded condition for long periods of time without starting and stopping or otherwise throttling the compressor.

It has heretofore been common practice to start and stop or otherwise throttle compressor operation in refrigeration systems in accordance with the demands. However, such on and off operation of the compressor is objectionable for vaious reasons including wear and tear on the compressor and the noise attendant such operation.

Accordingly, certain prior art attempts have been made to provide a system where in a refrigenant compressor can continue to operate in an unloaded condition without throttling the same. Some of these attempts have included a by-passing of some of the refrigerant to the suction line of the compressor accompanied by the use of expensive and elaborate desuperheater units for lowering the refrigerant temperature for introduction to the compressor suction line. However, overheating of the compressor has ordinarily occurred when such a desuperheater system is used in conjuction with an unloaded compressor over a long period of time.

Some prior art structures have also proposed various systems for by-passing limited quantities of refrigerant from the compressor discharge in response to conditions prevailing in the overall system, as shown for example, in US. Patents No. 1,786,791, dated December 30, 1930, No. 1,983,550, dated December 11, 1934, and No. 2,191,- 102, dated June 27, 1939.

In accordance with the present invention, a novel system has been developed wherein the by-passing of refrigerant fluid from the compressor discharge enables the compressor to run in an unloaded condition without starting and stopping the compressor, without throttling the compressor, or without otherwise disturbing the compressor operation whether it be in loaded or unloaded condition. Preferably, the by-passing of the fluid refrigerant occurs at a standpipe located on and communicating with the interior of the receiver of the system to which the refrigerant is conducted from a condenser in a manner well known in the art, and the refrigerant in the standpipe is cooled by pressure reduction so that it may be safely returned to the compressor suction side from the receiver in desuperheated condition so as not to overheat the compressor. A control valve in the conduit between the compressor suction and the standpipe is provided to maintain the desired pressure and thereby provide fluid refrigerant at low temperature for introduction to the compressor suction line. Thus, the operation of the compressor in an unloaded condition may be continuou without overheating the compressor, or without having to provide an elaborate desuperheater or other elaborate condition sensing systems for accomplishing the improved result of the invention.

It is, therefore, an object of the invention to provide an improved by-pass system for facilitating compressor operation in an unloaded condition.

It is another object of the invention to provide an improved by-pass system which contemplates the introduction of fluid refrigerant at relatively low temperatures from a refrigerant receiver to compressor suction during periods of no loads or low demand.

It is a further object of this invention to provide an improved system for continuously operating a refrigerant compressor in an unloaded constant condition.

These and other objects and advantages of the invention will become apparent from the following detailed description.

A clear conception of the several features constituting the present invention and of the mode of constructing and of operating compressor and refrigerant systems embodying the improvements may be had by referring to the drawings accompanying and forming a part of this specification, wherein like reference characters designate the same of similar parts in the various views.

FIG. 1 is a perspective view of a refrigerating system embodying the invention.

While the improvements have been illustrated and described as being especially advantageously embodied in a refrigerating system of a particular type, it is not intended to thereby unnecessarily limit or restrict the invention. It is also contemplated that certain descriptive terminology used herein shall be given the broadest possible interpretation consistent with the disclosure.

Referring now to the drawing, a refrigerating system is disclosed in which a refrigerant compressor 11 acts on the refrigerant gas to compress the same and discharge the refrigerant at high pressure through the line 12 in gas form. The usual one-way non-return check valve 14 is interposed in the discharge conduit 12 between the compressor 12 and the condenser 13 from which the refrigerant is discharged through conduit 15 to a receiver 16, and in accordance with usual practice, a check valve 17 may be interposed in conduit 15 between the condenser 13 and the receiver 16. The receiver 16 is also provided with a suitable liquid level indicating gauge 18, and an expansion valve 19 is provided in the conduit 20 leading from the receiver to the cooling coil or evaporator 21.

The refrigerant fluid is returned from the evaporator 21 through conduit 22 to the compressor suction line 23, to complete the refrigerant cycle.

When the demand of the evaporator 21 for refrigerant is either low or ceases entirely, the compressor 11 will operate in an unloaded condition, and in accordance with this invention, it is proposed to by-pass the refrigerant from the receiver directly to the suction line 23 of compressor 11 so that the operation of the compressor may remain substantially constant without having to throttle or start and stop the compressor. The supply of refrigerant thus by-passed from the receiver 16 through conduit 26 to the compressor suction line 23 and then introduced into the compressor suction is of reduced temperature compatible with eflicient compressor operation in its unloaded condition.

This invention also contemplates provision of a by-pass system which most effectively supplies the refrigerant at a predetermined temperature from the receiver to the suction side of the compressor, and for this purpose, a standpipe 25 is located on the receiver 16 and in communication with the interior thereof. A conduit 26 in turn connects the receiver standpipe 25 to the compressor suction line 23 for delivering the refrigerant to the compressor suction line. Interposed between the standpipe 25 and the compressor suction line 23 in conduit 26 is a reverse acting back pressure valve 27 set at a predetermined pressure to allow for cooling of the refrigerant in the standpipe. Such reduction in pressure in the standpipe permits the refrigerant to cool sufliciently for return to the compressor suction, and this reduced pressure condition also causes refrigerant fluid in the receiver to flash so that the refrigerant conducted from the standpipe to compressor suction when the compressor is operating at an unloaded condition is in gaseous condition.

Thus, a refrigerant system has been provided wherein a portion of the refrigerant from the compressor discharge side of the system is allowed, under reduced pressure conditions at a receiver standpipe, to return at a reduced temperature to the suction of a compressor operating at an unloaded condition whereby it is not necessary to stop and start the compressor, throttle the compressor, or otherwise utilize elaborate desuperating means in efforts to maintain the overall efficiency of refrigerant compressor operation.

Various modes of carrying out the invention are contemplated as being within the scope of the following claims particularly pointing out and distinctly claiming the subject matter which is regarded as the invention.

I claim:

1. In a refrigerating system, a low pressure portion including an evaporator, a high pressure portion including a condenser, a receiver interposed between said condenser and said evaporator, a normally continuously operating compressor having a low pressure inlet and a high pressure outlet for circulating refrigerant from the low pressure portion of the system to the high pressure portion thereof, and means responsive to conditions prevailing in the low pressure inlet for by-passing refrigerant from said receiver directly to the low pressure inlet of the compressor past said evaporator during periods of reduced load.

2. The refrigerating system of claim 1, wherein the refrigerant by-pass means includes means for reducing the temperature of the refrigerant conducted to the compressor inlet.

3. The refrigerating system of claim 1, wherein the refrigerant by-pass means includes a standpipe communicating with the interior of the receiver and a conduit connecting said standpipe directly to the compressor inlet.

4. The refrigerating system of claim 1, wherein the means for by-passing refrigerant from the receiver provides a sufficient amount of refrigerant to the low pressure inlet for the compressor to meet minimal load requirements.

5. The refrigerating system of claim 1, wherein the refrigerant by-pass means includes a valve interposed between the receiver and the low pressure inlet of the compressor and responsive to the prevailing conditions in said inlet for supplying the refrigerant to the compressor directly from the receiver during periods of unloaded conditions, whereby the temperature in the compressor inlet is reduced.

References Cited by the Examiner UNITED STATES PATENTS 2,871,673 2/1959 Richards 60509 X MEYER PERLIN, Primary Examiner. 

1. IN A REFRIGERATION SYSTEM, A LOW PRESSURE PORTION INCLUDING AN EVAPORATOR, A HIGH PRESSURE PORTION INCLUDING A CONDENSER, A RECEIVER INTERPOSED BETWEEN SAID CONDENSER AND SAID EVAPORATOR, A NORMALLY CONTINUOUSLY OPERATING COMPRESSOR HAVING A LOW PRESSURE INLET AND A HIGH PRESSURE OUTLET FOR CIRCULATING REFRIGERANT FROM THE LOW PRESSURE PORTION OF THE SYSTEM TO THE HIGH PRESSURE PORTION THEREOF, AND MEANS RESPONSIVE TO CONDITIONS PREVAILING IN THE LOW PRESSURE INLET FOR BY-PASSING REFRIGERANT FROM SAID RECEIVER DIRECTLY TO THE LOW PRESSURE INLET OF THE COMPRESSOR PAST SAID EVAPORATOR DURING PERIODS OF REDUCED LOAD. 